Urban sanitation coverage and environmental fecal contamination: Links between the household and public environments of Accra, Ghana

Abstract

Exposure to fecal contamination in public areas, especially in dense, urban environments, may significantly contribute to enteric infection risk. This study examined associations between sanitation and fecal contamination in public environments in four low-income neighborhoods in Accra, Ghana. Soil (n = 72) and open drain (n = 90) samples were tested for E. coli, adenovirus, and norovirus. Sanitation facilities in surveyed households (n = 793) were categorized by onsite fecal sludge containment ("contained" vs. "uncontained") using previous Joint Monitoring Program infrastructure guidelines. Most sanitation facilities were shared by multiple households. Associations between spatial clustering of household sanitation coverage and fecal contamination were examined, controlling for neighborhood and population density (measured as enumeration areas in the 2010 census and spatially matched to sample locations). E. coli concentrations in drains within 50m of clusters of contained household sanitation were more than 3 log-units lower than those outside of clusters. Further, although results were not always statistically significant, E. coli concentrations in drains showed consistent trends with household sanitation coverage clusters: concentrations were lower in or near clusters of high coverage of household sanitation facilities-especially contained facilities-and vice versa. Virus detection in drains and E. coli concentrations in soil were not significantly associated with clustering of any type of household sanitation and did not exhibit consistent trends. Population density alone was not significantly associated with any of the fecal contamination outcomes by itself and was a significant, yet inconsistent, effect modifier of the association between sanitation clusters and E. coli concentrations. These findings suggest clustering of contained household sanitation, even when shared, may be associated with lower levels of fecal contamination within drains in the immediate public domain. Further research is needed to better quantify these relationships and examine impacts on health.

Fig 1. Neighborhood sanitation coverage and sample sites, Shiabu, Accra, Ghana.

Drain sampling sites are illustrated using outlined circles. Households with a contained toilet are illustrated using black dots, while those without contained toilets (with uncontained toilets or no household sanitation facility present) are illustrated using white dots. Clusters of high (gray) and low (white) coverage of contained toilets are illustrated using ellipses. Although ellipses are drawn to estimate the locations of high- and low-coverage clusters, based on households inside/outside of the cluster, SaTScan software uses shape-based methodology (e.g. ellipses, circles) to scan the study area. Thus, the ellipse shape was selected a priori to allow for improved ability to scan irregularly-shaped areas (study neighborhoods). The software then scanned the study neighborhoods using ellipses of different sizes (up to 50% of the neighborhood’s households) to determine areas of significantly higher or lower coverage of the selected variable (any household sanitation, contained household sanitation) compared to the average of households not in that particular scan area (cluster) [48].